1. Field of Invention
The present disclosure relates in general to a system for selectively providing access to a wellbore annulus through a sidewall of a wellhead hanger. More specifically, the present disclosure relates to an annulus access valve in the side wall of a tubing hanger for controlling a flow of annular fluid.
2. Description of Prior Art
High pressure wellheads used in the production of hydrocarbons extracted from subterranean formations typically include a wellhead assembly attached at the upper end of a wellbore formed into a hydrocarbon producing formation. Wellhead assemblies usually provide support hangers for suspending production tubing and casing into the wellbore. The casing lines the wellbore, thereby isolating the wellbore from the surrounding formation, whereas the tubing usually inserts within the casing and provides a conduit therein for producing the hydrocarbons entrained within the formation. Wellhead assemblies also typically include a wellhead housing and a production tree atop the wellhead housing, where the wellhead housing circumscribes the hangers that support the casing and tubing. The production tree is commonly used to control and distribute the fluids produced from the wellbore, and to selectively provide fluid communication or access to the tubing, casing, and/or annuluses between the tubing and casing. Valves assemblies are typically provided within production trees for controlling fluid flow from a wellhead, such as production flow from the borehole or circulating fluid flow in and out of a wellhead.
Wellhead assemblies are usually mounted over a wellbore that intersects a subterranean formation and typically include a main bore that registers with the wellbore. Swab valves are generally set within the main bore for isolating the main bore and wellbore from ambient conditions above the wellhead assembly. Production from the wellbore is generally accomplished via a production line that intersects the main bore and extends laterally through a production tree. A production wing valve is generally provided within the production line for selectively regulating flow through the production flow line. Annulus line within a production tree usually includes an annulus wing valve for controlling flow therein. An annulus is defined between the tubing and casing which typically is in communication with the annulus line. Often, an annulus bleed line is included for annulus access or for venting of the annulus, and usually has one end connected to the annulus.